Stereocontrolled Construction of Quaternary Stereocenters by Inter- and Intramolecular Nitro-Michael Additions Catalyzed by Bifunctional Thioureas
作者:Rubén Manzano、José M. Andrés、María D. Muruzábal、Rafael Pedrosa
DOI:10.1002/adsc.201000612
日期:2010.12.17
A highly diastereo- and enantioselective conjugate addition of β-keto esters to nitroolefins, catalyzed by a chiral thiourea prepared from L-valine is described. The formation of two contiguous tertiary and quaternary stereocenters occurs in high yield and excellent diastereo- and enantioselection with only 2 mol% of catalyst loading. The reaction is general and different β-keto esters and aryl- and
描述了由由L-缬氨酸制备的手性硫脲催化的β-酮酯向硝基烯烃的高度非对映选择性和对映选择性共轭加成。两个连续的三级和四级立体中心的形成以高收率,极佳的非对映异构和对映异构发生,且催化剂负载量仅为2 mol%。该反应是一般的,并且已经测试了不同的β-酮酯以及芳基-和烷基硝基烯烃。相同的催化剂已被用于促进分子内共轭物的首次加成,从而导致中等非对映选择性和良好对映选择性的环状加合物。